microbiology
mikethemadbiologist | December 4, 2006The story about Kenyan religious leaders who are attempting to stifle evolutionary biology at the Kenyan National Museum is making the rounds of the progressive political blogs (interesting, how the right-wing blogs aren't covering this...). Within this story, there is a real tragedy: Kenya has a serious problem in treating certain types of bacterial dysentery due to the evolution of antibiotic resistance.
sporte | November 29, 2006What's the difference between a synthetic drug and an antibiotic?
Sometimes there's no difference at all.
Let's take a look at chloramphenicol and couple of pencillins.
Chloramphenicol kills many different kinds of bacteria by interfering with their ability to make new proteins. Here's a point where language gets tricky. Originally, chloramphenicol was isolated and purified from Streptomyces (a kind of bacteria). But, chloramphenicol is small and chemists are able to synthesize it. So even though we consider antibiotics to be natural products, they don't have to be made in a "natural…
sporte | November 28, 2006Antibiotics are molecules of biological warfare.
Produced by bacteria and some fungi, in response to extracellular signals, antibiotics represent a diverse group of compounds that inhibit bacterial growth at different points and different stages of the life cycle.
We will get around to antibiotic resistance, but in these few words, I think I already wrote quite a bit. Admittedly, some of these ideas need a bit of chewing, if they are to be properly digested. Already, I can imagine hands raised and questions waiting to be asked.
What are antibiotics made of?
I'm confused about this idea…
mikethemadbiologist | November 26, 2006As a part of the Carnival of the Liberals, I wrote a post about our failing political discourse. Here's something related from the archives.
In an excellent post on news reporting, Thoughts from Kansas writes (italics mine):
The same thing is a major part of the ongoing creationism battles. A good reporter with a background in science would not feel obliged to go to a scientist and get a quote to balance a story about creationists. Nor would such a reporter feel obliged to troll the waters for some bottom-feeding creationist to "balance" some claim about actual science.
But that's what many…
mikethemadbiologist | November 25, 2006One topic that I don't discuss enough is the role that the agricultural use of antibiotics plays in the evolution (and ecology) of antibiotic resistance. A recent review in Clinical Microbiology and Infection describes how the illegal use of nitrofuran antibiotics in Portugese agriculture led to an increase in highly virulent Salmonella.
What are nitrofurans? There are several different nitrofuran antibiotics (furazolidone, nitrofurazone, and nitrofurantoin), but the one drug some readers might have heard of (or taken) is nitrofurantoin, which is used to treat urinary tract infections, in…
mikethemadbiologist | November 24, 2006Here's some follow-up thoughts on my Salmonella-related moment of fame that I reposted yesterday
So while on vacation, I was mentioned in a NY Times article about diseases that can be caught from your fish tank. The moral of the story is when cleaning your fish tank, pretend it's toilet water, clean everything including the sink that comes in contact with the aquarium water, and you'll be fine. (Here's the Emerging and Infectious Disease article that led to the NY Times story).
I'm happy with the coverage: the issue of antibiotic resistance needs it. But one important message-that…
mikethemadbiologist | November 23, 2006Ok, so after complaining about how no one reads my posts on antibiotic resistance, one reader read this post about the FDA overriding an expert panel that advised against using cefquinome in agriculture, and then went and read the recently released minutes of the hearing (all eight gajillion pages). Here's what the director of the Center for Veterinary Medicine of the FDA said (p. 211; italics mine):
And so from the FDA standpoint, what we did was we said to the company after vetting it through the VMAC, that you will be judged -- the microbial safety of your product will be judged based on…
mikethemadbiologist | November 16, 2006A few weeks ago, an FDA expert panel by a vote of 6-4 decided against the approval of the use of the antibiotic cefquinome in cattle. Unfortunately, I've heard through the grapevine that the political appointees at the FDA plan to overrule the expert panel and approve the use of cefquinome. The chairman of the panel is under pressure to alter the panel's findings, and the FDA has not posted the minutes of the meeting, which is apparently required by law.
About the post title: cefepime, like cefquinome, is what is known as a fourth-generation cephalosporin antibiotic. While cefquinome is…
mikethemadbiologist | November 14, 2006...then what we think makes community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) so infectious might be wrong. A to-be published article in the Journal of Infectious Diseases (Dec. 15) asks "Is Panton-Valentine Leukocidin the major virulence determinant in community-associated methicillin-resistant Staphylococcus aureus disease?" Before everyone wanders off due to boredom, let me translate: we don't really understand how CA-MRSA can kill you.
The study, conducted by Jovanka Voyich and colleagues, examined the assumption that the Panton-Valentine Leukocidin toxin ('…
sporte | November 14, 2006A few weeks ago, I wrote about visiting the Dead Sea Scrolls exhibit at the Pacific Science Center and learning how DNA analysis is being used to help put pieces of the scrolls together.
One of the mysteries that was discussed in the exhibit was the question of whether the members of the religous sect living in nearby Qumran were the authors or at least the owners of the scrolls.
It appears that the owners left other clues behind that have answered this question.
One of the distinctive aspects of the Essenes, who lived in Qumran, was their obsession with achieving purity. So obsessed…
mikethemadbiologist | November 5, 2006There is absolutely nothing the Republicans won't politicize. Now, they have launched the War on Vaccination. For a decade, the Robert Wood Johnson Foundation, a foundation dedicated to improving public health, particularly among the poor and the elderly, has funded a "Vote and Vax" program at early voting facilities that serve poor neighborhoods in 24 cities. Basically, if you're over 50, you can get a vaccination at the polling location.
Thursday, in Houston, the Republicans filed a lawsuit to stop this program.
Nevermind that the program has been running for ten years. When the program…
mikethemadbiologist | November 1, 2006There's a very interesting article by Sheldon Campbell and Roger Klein in the October edition of The Journal of Clinical Microbiology about the pros and cons of home-testing for HIV. At first glance, this would only seem to be a good thing: after all, we use home pregnancy testing kits, so why not an HIV kit?
Well, like everything, there is good and bad. First, the potential bad outcomes:
(italics mine)
In the worst case, a rapid HIV test would be approved, but the real-world accuracy in the hands of intended users would be less than intended. The test would be expensive and heavily and…
mikethemadbiologist | October 26, 2006I have discussed the "search and destroy" strategy for controlling and reducing methicillin resistant Staphylococcus aureus (MRSA) before. Search-and-destroy involves the screening of every patient and hospital worker for MRSA.
Patients with MRSA are isolated to prevent spread to other patients. In the Netherlands, hospital workers with MRSA are sent home with pay, and are treated with muriopicin nasal drops (MRSA usually lives up your nose). In addition, the workers' family is screened along with any pets, and those that have MRSA are also treated. Because of this program, the…
mikethemadbiologist | October 23, 2006The NY Times recently had a very good article about strep throat, which is caused by group A streptococci (which, if I'm not mistaken are near and dear to fellow ScienceBlogling Tara). Sore throats are one of the leading causes of the overprescribing of antibiotics (it's been estimated that 20% of all antibiotic prescriptions are incorrectly prescribed to treat viral infections, including sore throats), which leads to the evolution of antibiotic resistant bacteria:
Symptoms of a strep throat and a sore throat caused by a virus can overlap (children may experience stuffy noses, coughs and…
mikethemadbiologist | October 19, 2006At least when it comes to killing young children in the developing world. A recent Lancet article describes the devastation pneumonia causes among children:
Pneumonia kills more children than any other illness, more than AIDS, malaria, and measles combined... More than 2 million children under 5 years of age die from pneumonia each year, accounting for almost one in five under-5 deaths worldwide. Yet few headlines report the effect of pneumonia on children's lives.
The world's attention has under standably turned to other major public-health scourges, such as HIV/AIDS, malaria, and…
mikethemadbiologist | October 18, 2006By day, I work for an organization that combats the spread of antibiotic resistant microorganisms. One source of antibiotic resistance is the misuse of antibiotics by patients. Often patients will stop using antibiotics early because they feel better. Not only does this make it more likely that the treatment will fail, but the bacterium has been exposed to a lower dose of antibiotics, selecting for 'intermediately' resistant organisms, which is often the first evolutionary step towards therapeutic resistance (i.e., the antibiotic won't work against these organisms).
But reading the…
mikethemadbiologist | October 3, 2006Inspired by this excellent post by Revere about the evolution of influenza, I've delved deep into the archives of the Mad Biologist, and summoned up some evolutionary thoughts of my own about influenza:
I meant to post something about evolution and influenza before my travels up north, but I was swamped by work and couldn't get to it. Thankfully, two colleagues, Carl Bergstrom and Marc Lipsitch, have decided to deal with Wendy Orent's faith-based virology. Orent writes (italics mine):
Indeed, a strictly enforced quarantine could do more harm than good. Herding large numbers of possibly…
mikethemadbiologist | September 30, 2006Since I'm going away for a long weekend, I'll leave you with this post about phage therapy from the archives.
So Aetiology, in her new digs, wants a post. Well, here's one, inspired by a comment: phage therapy. "Phage therapy" is short for bacteriophage therapy. Bacteriophage are viruses that kill bacteria (literally, "bacteria devourers"). The basic concept of phage therapy is to introduce the phage into an infected patient. The phage infect the bacterium-an infection of an infection! Then the phage multiply within the bacterium, lyse (explode from the inside) the host bacterium and…
mikethemadbiologist | September 25, 2006Do you want to know how to stop, or at least, lessen the next E. coli 0157:H7 outbreak? Improve our surveillance and public health infrastructure.
If we improve the infrastructure, we can speed the response time, making it easier to contain an outbreak.
Let's walk through each of the steps the CDC outlined in its response.
1. Incubation time: The time from eating the contaminated food to the beginning of symptoms. For E. coli O157, this is typically 3-4 days.
There's not much we can do to 'improve' this step. While random testing could be an option, when it comes to produce, I don't see…
mikethemadbiologist | September 25, 2006Most microbiologists, you know, the experts , are not very thrilled with the emphasis being placed on bioterrorism. Inspired by Tara's post on the Bioshield initiative, I'm reposting this from the old site.
This week, leading microbiologists are sending an open letter to NIH stating that the politically-based emphasis on bioterrorism is starving other areas of research. For some time now, I've thought that we've been too concerned with bioterrorism, particularly when good ol' influenza regularly kills 32,000 37,000 people per year (that's one World Trade Center per month for those of you…